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In-Situ Observation of Heavy-Oil Cracking using Backscattering Optical Techniques

  • Author / Creator
    Dinh, David Q.
  • An investigation was conducted on heavy oil cracking using polarized hot stage microscopy and laser dynamic backscattering. Both of these in-situ techniques were used to monitor cracking reactions through the use of backscattering. The use of hot stage microscopy resulted in a series of micrographs that were analyzed using the mean grey value (MGV). MGV is a parameter that reflects the average brightness of micrographs taken. Laser dynamic backscattering was also used and reported results using the depolarization ratio (DPR). DPR is the quotient of the parallel and perpendicular components of light after the initial incoming linearly polarized light is backscattered. Both optical techniques allowed for an examination of cracking kinetics, fouling behavior, mesophase onset and the effect of added water. The activation energies of low conversion cracking for several feeds (Cerro Negro crude oil, Safaniya vacuum residue (VR), Cold Lake VR, Athabasca VR, Gudao VR and Columbian VR), were calculated from several experiments at various temperatures (420°C to 450 °C) using both apparatus. Mesophase are anisotropic materials that appear as light domains on the micrographs, and were observed for all feeds given sufficient time for reaction. A second type of fouling only observed for Gudao VR and Columbian VR was dark film fouling which appeared as dark deposits and was observed before mesophase onset. Finally, water in the range of 12.9-23.4 wt% was added to Athabasca VR to investigate if water had any effect on cracking. It was found that the added water introduces phase instability and causes Athabasca VR to exhibit dark film fouling.

  • Subjects / Keywords
  • Graduation date
    2015-11
  • Type of Item
    Thesis
  • Degree
    Master of Science
  • DOI
    https://doi.org/10.7939/R3SF2MK85
  • License
    This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.
  • Language
    English
  • Institution
    University of Alberta
  • Degree level
    Master's
  • Department
    • Department of Chemical and Materials Engineering
  • Specialization
    • Chemical Engineering
  • Supervisor / co-supervisor and their department(s)
    • McCaffrey, William (Chemical Engineering)
    • Gray, Murray (Chemical Engineering)
  • Examining committee members and their departments
    • Semagina, Natalia (Chemical Engineering)